BRPI0620399B1 - Absorbent article and method of detecting the presence of an attack within an absorbent article - Google Patents

Abstract

personal care products with micro chemical sensors for odor detection. Absorbent articles comprising one or more sensors capable of detecting the presence of a body residue in the absorbent article are described. particularly, the absorbent articles comprise at least one chemosistor capable of detecting the presence of volatile organic compounds associated with a bodily residue. When a body residue is detected, an indicator means signals the caregiver and / or wearer of the absorbent article that an attack has occurred.

Description

'ABSORBENT ARTICLE AND METHOD OF DETECTIONING THE PRESENCE OF AN ATTACK WITHIN AN ABSORBENT ARTICLE' BACKGROUND This disclosure relates to absorbent articles such as diapers, training pants, incontinence clothing and feminine hygiene products, which include a or more sensors capable of detecting the presence of a bodily residue, such as urine, feces or menstruation, in the absorbent article More particularly, the present disclosure relates to absorbent articles comprising at least one chemosistor capable of detecting the presence of associated volatile organic compounds When the presence of a body residue is detected, an indicator means to a caregiver and / or user of the absorbent article that it needs to be replaced.

Disposable absorbent articles such as diapers, incontinence garments and feminine hygiene products are widely used. Such articles are used to capture and retain body wastes such as urine, feces and menstrual fluid for extended periods of time. However, body wastes can be irritating to the skin and are an important source of various types of bacteria. Consequently, when body wastes are kept in contact with the skin for prolonged periods of time, the skin may become irritated and may develop, for example, rashes (eg, rash, irritation, etc.) or other related conditions that may be present. caused by prolonged exposure to moisture, heat, irritants, enzymes, bacteria, bacterial action products and / or pressure.

In addition to causing skin conditions such as rashes, bacteria present in the residue can produce significant amounts of volatile organic compounds. Since human waste contains a large number of bacteria that may remain close to the skin upon release, these volatile organic compounds can also be a major source of skin irritants and may be involved in skin irritation in diaper and vaginal environments.

In addition, volatile organic compounds can be a significant source of unpleasant odors. For example, some bacteria produce ammonia, mercaptans, or other odorous compounds through the degradation of urine. Urine, for example, can also be used as a nutritional substrate by bacteria, resulting in the growth of more bacteria and production of more ammonia in a growing harmful cycle.

As such, it would be beneficial for caregivers and / or absorbent article wearers to know when an absorbent article has been attacked with bodily waste so that the caregiver and / or user can exchange the absorbent article, thereby reducing or eliminating unpleasant odors and irritation. of skin associated with the use of an absorbent article for an extended period of time. Thus, there is a need in the childcare, adult care, wound care, and feminine care industries for a method for quickly and accurately identifying the presence of a body residue in an absorbent article.

SUMMARY OF THE DISCLOSURE The present disclosure relates to absorbent articles, which comprise one or more sensors capable of detecting the presence of a bodily residue in an absorbent article. More particularly, the present disclosure relates to absorbent articles comprising at least one chemosistor capable of detecting the presence of volatile organic compounds associated with a body residue. When a body residue is detected, an indicator means signals to the caregiver and / or wearer of the absorbent article that an attack has occurred. As a result, the user and / or caregiver can quickly and accurately determine when the absorbent article needs to be changed.

In one embodiment, the present disclosure is directed to an absorbent article comprising a chemosistor arranged across a pair of spaced electrodes, the chemosistor comprising a plurality of electrically conductive particles and a polymeric material; a microprocessor capable of detecting a change in the chemoresistor's electrical resistance; and a means for signaling the presence of a change in the chemoresistor electrical resistance in the absorbent article. The resistance of the chemosistor is capable of changing when the chemosistor is exposed to an analyte selected from the group consisting of water vapor, a volatile organic compound present in an attack, and combinations thereof where the attack is selected from the group. consisting of urine, menstrual fluid, feces, blood and combinations thereof.

In another embodiment, the present disclosure is directed to an absorbent article comprising a chemosistor arranged across a pair of spaced electrodes, the chemosistor comprising a plurality of electrically conductive particles and a polymeric material; a microprocessor capable of detecting a change in the chemoresistor's electrical resistance; and a transmitter capable of sending a signal to a receiver at a location remote from the absorbent article, the receiver comprising means for signaling the presence of a change in the chemoresistor electrical resistance in the absorbent article. The resistance of the chemosistor is capable of changing when the chemosistor is exposed to an analyte selected from the group consisting of water vapor, a volatile organic compound present in an attack, and combinations thereof where the attack is selected from the group. consisting of urine, menstrual fluid, feces, blood and combinations thereof. The present disclosure is also directed to a method for detecting the presence of an attack on an absorbent article. The method comprises providing a user with an absorbent article comprising a chemosistor arranged across a pair of spaced electrodes, the chemosistor comprising a plurality of electrically conductive particles and a polymeric material; monitor an electrical property of the chemosistor as the absorbent article is being used by the user, where the chemosistor resistance is able to change when the chemosistor is exposed to an analyte selected from the group consisting of water vapor, an organic compound. volatile present in an attack and combinations thereof, where the attack is selected from the group consisting of urine, menstrual fluid, feces, blood and combinations thereof; determine a proportional difference in electrical property over time and provide a difference indicator value corresponding to the determined proportional difference; and comparing the difference indicator value to a difference limit value to determine the presence of attack and / or water vapor in the absorbent article. Also provided is a method for detecting the presence of an attack on the absorbent article. The method comprises providing a user with an absorbent article comprising a chemosistor arranged across a pair of spaced electrodes, the chemosistor comprising a plurality of electrically conductive particles and a polymeric material; monitor an electrical property of the chemosistor as the absorbent article is being used by the user, where the chemosistor resistance is able to change when the chemosistor is exposed to an analyte selected from the group consisting of water vapor, an organic compound. volatile present in an attack and combinations thereof, where the attack is selected from the group consisting of urine, menstrual fluid, feces, blood and combinations thereof; determine a rate of change in electrical property over time and provide a rate indicator value corresponding to the rate of change determined; and comparing the rate indicator value to a rate limit value to determine the presence of an attack and / or water vapor in the absorbent article.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a side view of an absorbent article of the present disclosure shown in the form of a pair of training pants having a mechanical closure system closed on one side of the training pants and open on the opposite side thereof; Figure 2 is a perspective view of the pants of Figure 1. Figure 3 is a perspective view of the pants, similar to Figure 2, showing a housing of a monitoring system removed from the article. Figure 4 is a top planar view of the training trousers of Figure 1 with the trousers in an open, unfolded condition showing the surface of the training trousers facing the wearer's side when dressed and with cut portions to show internal features. . Figure 5 is a cross-sectional view of the trousers taken along the plane including line 5 - 5 of Figure 4. Figure 6 is a schematic illustration of pants and one embodiment of a monitoring system of the present disclosure. Figure 7 is a block diagram of an embodiment of the disclosure illustrating an order of operation for components / devices of the disclosure including a metering device for measuring an electrical property of the pants and an analog to digital converter for converting an analog output of a measuring device in digital values to be read by a microprocessor. Figure 8 is a block diagram of exemplary instructions for the microprocessor of the present disclosure for determining the presence of an attack using a proportional difference in measured pants resistance. Figure 9 is a block diagram of exemplary instructions for the microprocessor of the present disclosure for determining proportional difference in resistance measured for the pants using successive resistance values. Figure 10 is a block diagram of exemplary instructions for the microprocessor of the present disclosure for determining the presence of an attack using a measured resistance resistance difference rate of the pants. Figure 11 is a block diagram of exemplary instructions for the microprocessor of the present disclosure for determining rate of change of resistance measured for pants using successive resistance values. Figure 12 is a block diagram of another embodiment of the present disclosure illustrating instructions for the microprocessor to determine if an attack has occurred. Figure 13 illustrates the relationship between dimethyldisulfide concentration (g / L) and resistance (ohms) of a chemosistor comprising polyvinylethylene acetate (PEVA).

Figures 14 to 17 illustrate the change in resistance when chemoresistors comprising polyvinylethylene acetate (PEVA) (Figure 14), poly-N-vinyl pyrrolidone (PVNP) (Figure 15), polyisobutylene (PIB) (Figure 16) or polypichlorohydrin ( PECH) (Figure 17) are exposed to various compounds commonly associated with urine and / or feces, as discussed in Example 1.

Corresponding reference characters indicate corresponding parts throughout the drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present disclosure relates to absorbent articles, which comprise one or more sensors capable of detecting the presence of a body residue or exudate such as urine, feces, menstruation and / or blood in the absorbent article. The absorbent articles comprise at least one chemosistor capable of detecting the presence of volatile organic compounds associated with bodily waste. When a body residue is detected, an indicator means signals to the caregiver and / or wearer of the absorbent article that an attack has occurred. As a result, the user and / or care can quickly and accurately determine when an insult occurs. The present disclosure is discussed primarily in combination with children's toilet training pants. However, it will be readily apparent to those skilled in the art based on the disclosure that the chemoresistors described herein may also be used in combination with numerous other absorbent articles. As used herein, the term "absorbent article" generally refers to devices that can absorb and contain body fluids, and more specifically refers to devices that are placed against or near the skin to absorb and contain the various released fluids. through the body. Examples of other absorbent articles include personal-use absorbent articles such as diapers, incontinence products, medical garments, feminine hygiene products such as handkerchiefs, panty liners, interlabial tampons and pads, wound care products, pads and pads. surgical bandages, other personal or health care clothing and the like.

Referring now to the drawings and particularly to Figure 1, an absorbent article of the present disclosure is representatively illustrated herein in the form of children's bathroom training pants and is indicated in its entirety by reference numeral (20). The absorbent article 20 may or may not be disposable, which refers to articles which are intended to be disposed of after a limited period of use rather than being washed or otherwise conditioned for reuse.

By way of illustration only, various materials and methods for constructing training pants such as pants 20 of various aspects of the present disclosure are disclosed in PCT Patent Application WO 00/37009, published June 29, 2000 by A. Fletcher et al., US Patent No. 4,940,464, filed July 10, 1990 to Van Gompel et al., US Patent Number 5,766,389 filed June 16, 1998 for Brandon et al., And US Pat. 6,645,190, filed November 11, 2003 to Olson et al., which are incorporated herein by reference. The pair of training pants 20 is shown in Figure 1 in a partially closed condition. The pants (20) define a longitudinal direction (48) of the pants and a lateral direction (49) thereof, perpendicular to the longitudinal direction as shown in Figure 4. The pants (20) further define a pair of longitudinal end regions of otherwise referred to herein as the front waist region generally indicated at (22) and a rear waist region generally indicated at (24) and a central region otherwise referred to as the crotch region generally indicated at (26) extending longitudinally between and interconnecting the front and back waist regions (22) and (24). The front and back waist regions (22) and (24) comprise those portions of pants (20) that, when worn, completely or partially cover or surround the wearer's waist or lower middle torso. The crotch region (26) is generally that portion of the pants (20) which, when worn, is positioned between the wearer's legs and covers the wearer's lower torso and crotch. The pants (20) also define an inner surface (28) that faces towards the wearer when the pants are being worn, and an outer surface (30) opposite the inner surface. Referring further to Figure 4, the pair of training pants (20) has a pair of laterally opposite side edges (36) and a pair of longitudinally opposite waist edges (broadly longitudinal ends), respectively referred to as the front waist edge ( 38) and posterior waist edge (39).

In the illustrated embodiment of Figures 1 to 4, the training pants 20 comprise a generally rectangular central absorbent assembly, generally indicated at 32, and separately formed side panels 34A, 34B attached to the central absorbent assembly. . The side panels (34A, 34B) are permanently attached along seams to the central absorbent assembly (32) in the respective front and back waist regions (22 and 24) of the pants (20).

More particularly, the front side panels 34A may be permanently attached to and extend transversely outwardly beyond the side margins 47 of the absorbent assembly 32 in the front waist region 22 and the rear side panels 34B ) may be permanently attached to and extending transversely outwardly beyond the lateral edges of the absorbent assembly in the rear waist region (24). Side panels 34A and 34B may be attached to the absorbent assembly 32 using fastening means known to those skilled in the art, such as adhesive, thermal or ultrasonic bonding.

The front and rear side panels (34 and 34B) under wear of the pants (20) thus include the portions of the training pants (20) which are positioned on the wearer's hips. The front and rear side panels (34 and 34B) may be permanently connected to each other to form the three-dimensional configuration of the pants (20), or may be releasably connected to each other, such as by the closure system (59) of the illustrated aspects. As is known in the art, side panels 34A, 34B may comprise elastic material or stretch but inelastic materials. The absorbent assembly 32 is shown in Figures 1 to 3 as having a rectangular shape. However, it is contemplated that the absorbent assembly 32 may be of other shapes (e.g., "T" hourglass, "I" shape and the like) without departing from the scope of this disclosure. It is also understood that side panels 34A, 34B may instead be integrally formed with the absorbent assembly 32 without departing from the scope of this disclosure.

As best shown in Figures 4 and 5, the absorbent assembly (32) comprises an outer cover (40) and a body side liner (42) attached to the outer cover (40) in a relationship superposed (opposite) thereto by adhesives. , ultrasonic bonds, thermal bonds, pressure bonds or other conventional techniques. The jacket (42) is suitably joined to the outer cover (40) along at least a portion of the longitudinal ends of the pants (20). Additionally, the liner (42) is suitably joined to the outer casing (40). The lining (42) is suitably adapted, i.e. positioned relative to other pants components (20), for continuous relationship with the wearer's skin while wearing the pants. The absorbent assembly (32) also comprises an absorbent structure (44) disposed between the outer cover (40) and the body side liner (42) for absorbing user-exuded, liquid body exudates and an outbreak management layer (45). ) disposed between the absorbent structure and the body side liner. A pair of retaining tabs (45) are attached to the body side liner (42) to inhibit lateral flow of body exudates.

With the training pants (20) in the closed position as partially illustrated in Figure 1, the front and rear waist regions are connected by the closure system (59) to define the three-dimensional pants configuration having a waist opening (50) and a pair of leg openings (52). The front and back waist edges (38 and 39) (e.g., longitudinal ends) of the training pants (20) are configured to encircle the wearer's waist to define the waist opening (50) (Figure 1) of the pants.

As illustrated in Figure 4, an elastic tab member (53) may be operably attached to each containment tab (46) in any suitable manner as is well known in the art. Suitable constructions and arrangements for the containment flaps 46 are generally well known to those skilled in the art and are described in U.S. Patent No. 4,704,116, issued November 3, 1987 to Enloe, which is incorporated herein by reference.

To further improve the containment and / or absorption of body exudates, the training pants (20) may comprise a front waist elastic element (54) (Figure 1) and a rear waist elastic element (56), and elastic waist elements. leg (58) (Figures 2 to 4), as known to those skilled in the art. Flap elastic members 53, waist elastic members 54 and 56, and leg elastic members 58 may be formed of any suitable elastic material which is well known to those skilled in the art. The closure system (59) of the illustrated embodiment comprises the first laterally opposed closing elements (60) adapted for resealable joining to corresponding corresponding laterally opposite closing elements (62). In one embodiment, a front or outer surface of each of the closure elements (60, 62) includes a plurality of joining elements. The joining elements of the first closure elements (60) are adapted to repeatedly join and disengage the joining elements of the second closure members (62) to releasably lock the trousers (20) in their three-dimensional configuration. The closure members 60, 62 may comprise any resealable closures suitable for absorbent articles such as adhesive closures, cohesive closures, mechanical closures or the like. Suitable closure systems are also disclosed in previously incorporated PCT Patent Application WO 00/37009 published June 29, 2000 by A. Fletcher et al. And previously incorporated US Patent No. 6,645,190 issued November 11, 2003 to Olson and others. The outer cover 40 suitably comprises a material that is substantially impermeable to liquid. The outer cover 40 may comprise a single layer of liquid impermeable material or, more suitably, may comprise a multilayer laminate structure wherein at least one of the layers is liquid impermeable. While it is not a necessity for the outer layer to be liquid permeable, it is suitable for it to provide a relatively similar texture to the wearer. Alternatively, the outer cover 40 may comprise a layer of nonwoven fibrous cloth or fabric that has been fully or partially treated or constructed to impart desired levels of liquid impermeability to selected regions that are adjacent to or near the absorbent structure. The outer cover 40 may also be stretchable and, in some embodiments, it may be elastomeric. Reference is made to US Patent No. 5,883,028 issued to Morman et al., US Patent Number 5,116,662 issued to Morman and US Patent No. 5,114,781 issued to Morman, all of which are incorporated herein by reference, for additional information regarding the appropriate external cover materials. The body side lining (42) is suitably flexible, soft in touch and non-irritating to the user's skin. The body side lining (42) is also sufficiently liquid permeable to allow liquid body exudates to readily penetrate through its thickness to the absorbent structure (44). The body side liner 42 may also be stretchable and in some embodiments may be elastomeric. Reference is made to Patent Application Serial No. 09 / 563,417, filed May 3, 2000 by Roessler et al., US Patent Application number 09 / 698,512, filed October 27, 2000 by Vukos and others. , both of which are incorporated herein by reference, for additional information regarding the body side liner material. The absorbent structure (44) is disposed between the outer cover (40) and the body side lining (42) which may be joined by any suitable means such as adhesives, ultrasonic bonding, thermal bonding. , or the like. Although the illustrated absorbent structure (44) is shown and described herein as extending from the crotch region (26) into both the front and back waist regions (22 and 24), it is considered that the absorbent structure may extend from the crotch region within only the front waist region, or only the rear waist region, without departing from the scope of this disclosure. The absorbent structure 44 may be suitably compressible, conformable, non-irritating to a user's skin, and capable of absorbing and retaining liquids and certain body wastes. For example, the absorbent structure 44 may comprise cellulosic fibers (e.g., wood pulp fibers), other natural fibers, synthetic fibers, woven or non-woven sheets, yarn or other stabilizing structures, superabsorbent material, binder materials , surfactants, selected hydrophobic materials, pigments, lotions, odor control agents, as well as combinations thereof.

The materials may be formed into an absorbent matting structure employing various conventional methods and techniques known in the art. For example, the absorbent structure 44 may be formed by a dry forming technique, an air forming technique, a wet forming technique, a foam forming technique, and the like, as well as combinations thereof. Methods and apparatus for performing such techniques are well known in the art. The absorbent structure (44) may alternatively comprise a co-shaped material such as the material disclosed in U.S. Patent Nos. 4,100,324 to Anderson et al .; 5,284,703 to Everhart et al; and 5,350,624 to Georger et al; which are incorporated herein by reference. The superabsorbent material is suitably present in the absorbent structure (44) in an amount from about 0 to about 90% by weight based on the total weight of the absorbent structure. The absorbent structure 44 may suitably have a density within the range of from about 0.10 to about 0.35 grams per cubic centimeter. Superabsorbent materials are well known and can be selected from polymers and modified natural, synthetic and natural materials.

In one aspect, the absorbent structure (44) may be stretchable so as not to inhibit the stretching ability of other components to which the absorbent structure may be adhered, such as the outer cover (40) and the body side liner. (42). For example, the absorbent structure may comprise the materials disclosed in U.S. Patent Nos. 5,964,743, 5,645,542, 6,231,557, 6,362,389 and International Patent Application WO 03/051254, the disclosure of which is incorporated herein by reference. The surge management layer (45) may be attached to various components of the article (20), such as the absorbent structure (44) and / or body side coating (42) by methods known in the art, such as adhesive bonding, ultrasonic or thermal. An surge management layer (45) helps to slow down and diffuse surges or liquid flows that can be rapidly introduced into the absorbent structure (44) of the article (20). Desirably, the surge management layer (45) can readily accept and temporarily retain the liquid before releasing the liquid into the storage or retention portions of the absorbent structure (44). Examples of suitable outbreak management layers (45) are described in U.S. Patent No. 5,486,166 and U.S. Patent No. 5,490,846. Other suitable outbreak management materials are described in U.S. Patent No. 5,820,973. The entire disclosures of these patents are incorporated herein by reference.

Optionally, a substantially liquid permeable wrapper sheet (not shown) may surround the absorbent structure (44) to help maintain the integrity of the absorbent structure (44).

The absorbent articles of the present disclosure comprise a monitoring system for detecting the presence of an attack (e.g., urine stool, menstrual fluid and / or blood, etc.) on the absorbent article. Generally, one or more chemical sensors are used to detect the presence of an attack-associated compound. The system monitors an electrical property of the chemical sensor (eg resistance and / or conductivity, etc.) and based on changes in electrical property determines whether the absorbent article has been attacked. After detecting the presence of the attack, a caregiver and / or user of the absorbent article is flagged for the presence of the attack. The signal may be, for example, an audio signal such as a song, a tactile signal such as a change in temperature, pressure or vibration, and / or a visual signal such as a flashing light, a visual message and the like. It will be understood that other signals are within the scope of the present disclosure.

Although mainly discussed in terms of detecting the presence of an attack, the monitoring system can also be used to detect the presence of water vapor in the absorbent article. As will be appreciated by those skilled in the art, high levels of water vapor may adversely affect the comfort level of the absorbent article wearer. Water vapor may be present in the absorbent article as a result of the wearer's perspiration or perspiration and / or may result from certain attacks, such as urine. By detecting the water vapor level in the absorbent article, a user and / or caregiver can monitor the user comfort level of the absorbent article.

Monitoring systems can furthermore be used to differentiate between types of attacks. As discussed herein, absorbent articles may comprise more than one sensor. In certain embodiments, different sensors in the same absorbent article may be sensitive to compounds associated with different attacks. For example, the absorbent article may comprise a sensor that is capable of detecting compounds associated with a different type of attack and may further comprise a different sensor that is capable of detecting compounds associated with a different type of attack. In this example, the caregiver and / or wearer of the absorbent article may be flagged when the presence of one or both attacks is detected. In certain embodiments, the signal may differ depending on the attack, so that the caregiver and / or user can determine by the type of signal what type of attack has been detected.

The sensors used here are chemoresistors. Generally speaking, a "chemosistor" is a dirty resistor. Electrical resistance varies when exposed to molecules of one or more chemical species. The chemoresistors comprise a chemoresistant material disposed through or between at least one pair of spaced electrodes. The chemoresistive material comprises a plurality of electrically conductive particles suspended in a polymeric material that is sensitive to the absorption or adsorption of a particular analyte (e.g., a volatile organic compound, water vapor, etc.). When the analyte absorbs or adsorbs on the polymeric material, the polymeric material swells. This swelling increases the spacing between the adjacent electrically conductive particles present in the chemosistor, which results in an increase in electrical resistance in the chemosistor. This change in resistance (or a corresponding change in other electrical property such as conductance) may be measured and recorded and used to signal a caregiver and / or wearer of the absorbent article when an attack has occurred. Since this process is reversible (that is, the analyte can desorb from the polymeric material, thereby reducing the resistance of the chemosistor), the chemosistor can be used to detect multiple attacks.

The chemoresistors of the present disclosure are selected to be sensitive to the absorption and adsorption of certain volatile organic compounds (VOCs) and in particular are selected to be sensitive to VOCs that are associated with particular body waste or exudate such as urine, feces, menstrual fluid and / or blood. As used herein, the term "volatile organic compound" is intended to include both organic and inorganic metabolic gases produced by microbes present in bodily waste. Particular VOCs may be associated with one or more types of body waste. VOCs commonly associated with urine include, for example, ammonia compounds (eg ammonium hydroxide), (C1 -C2) short acids (e.g. acetic acid), medium length (C8 -C10) aldehydes (eg nonanal), ketones (e.g. methyl ethyl ketone), cresol (e.g. methylphenol), dimethyl disulfide, trimethylamine, limonene (e.g. 4-isopropenyl-1-methylcyclohexane), acetic acid, methyl beanzoate, benzamide, benzaldide and triethylamine, among others. VOCs commonly associated with faeces include, for example, eschatol (eg, 3-methyl-1H-indole, 3-methylindole etc.), mercaptans (eg mercaptoethanol), hydrogen sulfide, short chain fatty acids (eg myristic acid), methanediol (e.g. 2-mercaptoethanol), and dimethyl sulfide, among others. VOCs commonly associated with menstrual fluid include, for example, trimethylamine, among others. The specificity of a chemosistor for a particular VOC depends on the polymeric material used in the chemosistor. In general, different polymers will absorb or adsorb VOCs with varying degrees of specificity. Suitable polymeric materials are typically selected first by determining the chemical properties of the VOC to be detected, for example, whether the VOC is hydrophilic or hydrophobic, the polarity of VOC, VOC functional groups, etc. Preferably, the chemical properties of the selected polymeric material are similar to the properties of the VOC to be detected.

In one embodiment, the polymeric material may be selected based on its solubility parameters, (5) which is preferably about the same as the VOC solubility parameter to be sorbed by the polymeric material. When the solubility parameters (6) of the polymeric material and the VOC are approximately the same, there will be substantial interaction between the polymeric material molecules and the VOC, thus leading to substantial VOC sorption in the polymeric material. Solubility parameters, (5), for various polymers and VOCs can be determined from simple experiments, can be readily computed, or can be determined from tables in chemical reference books (see also US Patent No. 6,902,701. , incorporated herein by reference). The compatibility of a particular polymer for detecting a VOC can also be readily and readily determined by one skilled in the art, experimentally based in part on what is disclosed herein. For example, once a polymer having similar chemical properties to those of the VOC to be detected has been selected, a chemosistor comprising the polymer can then be tested (for example using a method such as that described in the examples herein) to determine if There is a change in resistance when the chemosistor is exposed to VOC. Polymers that result in a high resistance change are preferably used in the chemosistor. The change in resistance (or other electrical properties as noted above) of the chemosistor in the presence of a target VOC is particularly dependent on VOC concentration. For example, chemoresistor resistance will generally increase when exposed to increasing concentrations of the target VOC. An example of this is illustrated in Figure 13, which shows the relationship between the concentration of the dimethyldisulfide VOC and the resistance of a chemosistor comprising polyvinyl ethylene acetate (PEVA). It is generally preferred that a chemoresistor of the present disclosure be able to detect target VOC (e.g., by exhibiting an increase in resistance in the presence of target VOC or by exhibiting a change in another electrical property, such as conductivity) at a target VOC concentration of at least minus about 1 ppm.

Particular polymeric materials that may be used to form chemoresists used in the present disclosure include polyepichlorohydrin (PECH), poly-N-vinyl pyrrolidone (PVNP), polyisobutylene (PIB), polyvinyl ethyl acetate (PEVA), polyvinyl alcohol (PVA), ethylcellulose (EC), and polydiphenoxyphosphaazine (PDPP). Preferably, the polymeric material is selected from the group consisting of PECH, PVNP, PIB and PEVA.

In addition to sipping VOCs in particular, certain polymers may also be water vapor sensitive. Consequently, water vapor (for example, from user perspiration or from the external environment) may also be sorbed by the polymeric material and affect the resistance of the chemosistor. As discussed above with respect to VOCs, the sensitivity of a polymeric material to water vapor will depend on the chemical properties of the polymeric material. For example, chemistors comprising PNVP are sensitive to water vapor (ie, they have a change in resistance when exposed to saturated water vapor), while chemoresists comprising PEVA, PIB and PECH show little change in resistance when exposed to steam. 'saturated water. By incorporating a water vapor sensitive chemosistor into an absorbent article, the user comfort level of the absorbent article can also be monitored.

As discussed above, a polymeric material may be selected to provide high sensitivity or selectivity for detecting a particular VOC by combining the chemical properties of the polymeric material with those of the VOC to be detected. Thus, in one embodiment, the absorbent articles of the present disclosure may comprise a single chemosistor that is sensitive to a particular type of VOC. For example, PECH is particularly sensitive to aromatic and chlorinated hydrocarbons as well as benzaldehydes. PVNP, a polar compound, is sensitive to polar VOCs such as trimethylamine, benzaldehyde, ammonia, mercaptans and water vapor. PIB and PEVA are hydrophobic and are sensitive to hydrophobic VOCs such as limonene and benzaldehydes. GDP is also sensitive to nonpolar VOCs.

Additionally, the absorbent articles of the present disclosure may comprise a single chemosistor that is sensitive to the presence of more than one type of VOC. For example, a particular polymeric material may be sensitive to a class of VOCs that share similar functionality or chemical subgroups in its structure. A chemosistor comprising such a polymer may show a resistance change when exposed to any of several VOCs in the class. However, the degree of change will typically be different for each individual VOC. For example, a polymer will typically be more responsive to a particular VOC than other VOCs, even if it shows some change in resistance to more than one VOC in the class. Consequently, if multiple types of VOCs are to be detected, it is generally preferable to use a different chemosistor for each individual VOC.

In another embodiment, the absorbent articles of the present disclosure may comprise more than one chemosistor. In this embodiment, the chemoresistors may each be sensitive to different VOCs or, alternatively, some or all chemoresistors may be sensitive to the same VOC. For example, the absorbent article may comprise multiple chemoresistors, some or all of which are sensitive to the same VOC, where the chemoresistors are located in different areas of the absorbent article, as discussed below. In another embodiment, the absorbent article may comprise two or more chemoresistors, with some or all of the chemoresistors being sensitive to VOCs associated with different types of attacks. In this example, chemoresistors can be used to differentiate between different types of attacks based on the detected VOC.

In addition to the polymeric material, the chemoresistive material further comprises a plurality of electrically conductive particles. Electrically conductive particles provide multiple ripple paths for an electric current to flow when an oltting is applied between the spaced electrodes. Electrically conductive particles are evenly distributed throughout the bulk of the material.

Preferably, the chemoresistant material comprises from about 20 wt% to about 60 wt% and more preferably from about 30 wt% to about 50 wt% of electrically conductive material. In general, any electrically conductive material can be used. Suitable electrically conductive materials are known in the art and include, for example, carbon (e.g. graphite), metallic particles such as silver, semiconductor laterals and the like. Preferably, the electrically conductive material comprises carbon particles. The exact size of the electrically corrugated particles is not critical, but is usually about 1 micrometer to about 10 micrometers. The chemoresistant material can typically be prepared by dissolving the polymeric material and electrically conductive particles in a solvent. [Typically, the solvent will have approximately the same solubility parameter as the polymeric material. Suitable solvents may be readily identified by one skilled in the art based on the polymeric material used. For example, water is a particularly suitable solvent for polar polymers such as PNVP. Trichlorethylene (TCE) can be used as a solvent for PECH, PEVA and PIB. Other suitable solvents may be readily determined by one skilled in the art.

In a non-limiting example, the chemoresistant material may be prepared by dissolving the polymeric material in the solvent. This may be done by mixing the polymeric material and solvent and heating the resulting mixture to approximately 40 ° C or, alternatively, the polymeric material may be left to dissolve in the solvent without heating. After the polymeric material is dissolved, an amount of electrically conductive particles may be added to the mixture to form a liquid chemoresistant material. In one example, the mass of electrically conductive particles and polymer may total about 0.1 g and may be mixed in about 5 mL of solvent.

As discussed above, the electrically conductive particles are preferably evenly distributed throughout the polymeric material. In one embodiment, a surfactant as a nonionic surfactant may optionally be added to the mixture of liquid chemoresistant material to help prevent aggregation or agglomeration of electrically conductive particles or migration of these particles towards the electrodes when voltage is applied to the chemosistor. In addition, the liquid chemoresistant material may optionally be sonicated to disperse the electrically conductive particles throughout the polymeric material and to help prevent formation of agglomerated colloids. Additionally, the liquid chemoresistant material may optionally be filtered to remove any agglomerated colloid formed by the electrically conductive particles. Filtration may be performed using, for example, a filter with a pore size of about 5 µm. The liquid chemoresistant material is then disposed in the absorbent article through or between a pair of spaced electrodes. The term "spaced" means that the electrodes do not touch each other directly. Although chemoresistant material is generally disposed through the electrodes, it will be recognized that chemoresistive material may also be disposed between the electrodes. In this example, the chemoresistant material should be close enough to each electrode so that the chemoresistant material is in electrical connection to the electrodes (for example, form a circuit as discussed below). Thus, as used herein, the phrase "disposed through a pair of spaced electrodes" is intended to include examples where the resistive material is disposed across and / or between the electrodes so that the resistive material is in electrical connection with the electrodes.

The electrodes may be constructed of any material that is generally electrically conductive. For example, the electrodes may be constructed of metal strips (eg aluminum strips), metal films, metallic wire, metal foil, coated films, conductive polymers, conductive inks or conductive filaments, among others. Other electrodes are within the scope of this disclosure. The electrodes may be attached to the absorbent article by any suitable means including, for example, using adhesives, imprinting the electrodes on a suitable surface of the absorbent article, and the like. Liquid chemoresistant material may be deposited by electrodes by any suitable means, including, for example, spin coating, spray coating, ink jet depositing, printing, etc. Preferably the chemoresistant material is deposited through the electrodes by impression. The chemosistor may be located on any suitable surface of the absorbent article. Preferably, the chemoresistive material is deposited on a non-porous surface of the absorbent article such as the outer covering. In one embodiment, the chemoresistant material is deposited on the surface facing the absorbent side of the outer cover to form a chemoresistor. Since the outer casing may be composed of a "breathable" material that allows vapors to escape from the absorbent body while preventing liquid exudates from passing through the outer casing, VOCs from an attack on the absorbent article may still reach the chemosistor passing through the casing. external. Thus, the chemoresistive material may alternatively or additionally be deposited on the outer surface of the outer cover to form a chemosistor.

Optionally, when the chemosistor is located on the outer surface of the outer cover of the absorbent article, the chemosistor may be covered with a coating comprising, for example, a non-breathable, non-porous substrate such as film or printed or layered material. Such a coating assists in the isolation of the chemoresistant material from the external environment and reduces the likelihood of the polymeric material sipping any VOC or water vapor from the external environment. The specific location of the chemosistor in the absorbent article is not limited and will vary depending on the VOC and body residue to be detected and the type of absorbent article. For example, in a preferred embodiment, a chemosistor may be located in the crotch region of the absorbent article, as illustrated in Figures 2 to 4. Alternatively, or additionally, a chemosistor may be located in other regions of the absorbent article.

One or more chemoresistors described herein form a part of the moisture monitoring system. In general, the monitoring system comprises a circuit. The chemoresistive material is arranged through a pair of spaced electrodes that are electrically connected to a current source. A measuring device measures an electrical property of the circuit, for example resistance, conductance, voltage, etc., and sends a signal containing information on the electrical property to a microprocessor. The microprocessor analyzes the signal to determine if an attack has occurred. If the microprocessor determines that an attack has occurred, an indicator means (also called an attack alarm here) is activated to indicate to the caregiver and / or user of the absorbent article whether the attack is present. Alternatively, the microprocessor, in determining that an attack has occurred, may activate a transmitter, which may then send a signal that an attack has occurred to a receiver at a remote location. The receiver then activates an indicator means to signal a caregiver or wearer of the absorbent article to the presence of the attack.

As will be apparent from this discussion, the components of the monitoring system (eg, measuring device, microprocessor, analog to digital converter, indicating means and / or transmitter, etc.) may be housed together or separately, and attached to the article. Absorbent. Alternatively, certain monitoring system components may be present at a remote location. For example, in one embodiment, the metering device, microprocessor, analog-to-digital converter and / or transmitter are housed together or separately and attached to the absorbent article, while the receiver and / or indicating means are housed together or separately at a remote location. . As used herein, the term "remote site" means that the components are not attached to the absorbent article. For example, in one embodiment, the receiver and / or indicating means may be housed in a transportable unit that may be maintained with the caregiver. Examples of such a unit may include an alarm such as a bedside alarm, alarm clock, "beep" or "Pa9er" / a lamp, a wall clock and the like.

In a particularly suitable embodiment, best shown in Figures 2 to 4, an example of the moisture monitoring system is generally indicated by the numerical reference (70). The monitoring system 70 includes a chemosistor 72 to detect the presence of a VOC associated with an attack, as discussed above. The chemosistor (72) is disposed in the crotch region (26) through a pair of spaced electrodes (E1) and (E2). The electrodes (E1 and E2) extend from the chemosistor (72) in the crotch region (26) to the trouser waist region (22) of the pants (20). As best shown in Figure 5, the electrodes (E1 and E2) may be disposed on the outer surface of the outer casing, although the electrodes (and chemoresistors) may be disposed elsewhere, as discussed above, without departing from the scope of this disclosure. Current (i) from a current source (B) (shown schematically in Figure 6) flows through electrodes E1, E2). The current source (i) may be a direct current source such as a battery (as shown), or an alternating current source. In a polished mode, the electrodes (E1, E2) are electrically connected to the current source by means of electrically conductive relay closures (79). However, any suitable means for electrically connecting the electrodes to the current source are within the scope of this disclosure such as a clip connector, corrugated hook and loop fasteners, conductive adhesives (e.g., corrugating tape) and the like. As shown in Figure 3, the corresponding end of each electrode (E1, E2) is connected to a first snap closure member 79A) located in the front waist region (22) of pants 20). Alternatively, the first relay closure element (or other connecting means) may be located at the rear waist portion (24), or at other suitable locations on the pants (20). A housing unit (82) housing the current source (i) has a corresponding second pressure echo element (79B) to engage the first snap closure (79A) and secure the housing to: the handle (20) . In addition to the current source (i), the housing unit (82) of the present embodiment may also house the remaining components of the moisture monitoring system (70) which will be described below, although, as discussed above, it is considered that the housing unit may include only some or none of the remaining components. In the illustrated embodiment the housing unit 82 is releasably secured to the trousers 20 by means of snap fasteners 79, although it is understood that the housing unit may be releasably attached to the article. absorbent by other means, such as conductive clips, hook and loop fasteners, conductive adhesives (e.g., conductive tape) and the like or, alternatively, may be permanently attached to the absorbent article by any suitable means, without departing from the scope of this disclosure. In one embodiment, when the housing unit is releasably attached to the absorbent article, the housing unit may be reused, for example, by securing the housing unit to a new absorbent article when the old absorbent article is changed. .

In certain embodiments, the absorbent article may comprise two or more chemoresistors. In this example, the chemoresistive material of the first chemosistor may be disposed through a first pair of spaced electrodes and the chemoresistive material of at least one additional chemosistor may be arranged through at least a different pair of spaced electrodes. Each pair of spaced electrodes may then be connected to the current source as discussed above.

A measuring device (Figure 6) measures an electrical property of the circuit. In one embodiment, the resistance (R) of the chemosistor (72) is measured. Because the electrodes (El, E2) are spaced apart, current from the current source (i) must pass through the chemosistor (72) to complete the circuit. As discussed above, when a VOC is absorbed or adsorbed by the chemosistor polymer material, the polymer material swells. This swelling increases the spacing between the adjacent electrically conductive particles present in the chemosistor, which results in an increase in electrical resistance in the chemosistor. This change in resistance can be monitored and used to determine if an attack is present on the absorbent article. Although discussed primarily in terms of resistance, other electrical properties of the circuit, including voltage, conductivity, and impedance, among others, may also change based on a change in chemoresistor resistance. Accordingly, these electrical properties may also be measured and used to determine if the attack is present on the absorbent article, without departing from the scope of this disclosure. The metering device 85 produces an analog output signal (Figure 6), indicative of the electrical property of the circuit being measured. For example, the measuring device 85 may measure a voltage drop across the chemoresistors 72 and produce an analog output signal corresponding to the voltage drop. The voltage output end can be used to determine other electrical properties, such as resistance or conductivity, by performing appropriate calculations known in the art or by using a reference table. For example, as is well known in the art, the voltage drop is indicative of the chemoresistor resistance when the current is constant. Thus, as explained below in more detail, the resistance of the chemosistor (72) can be determined using the analog output signal of the measuring device (85).

In one embodiment, illustrated in Figure 7, an analog-to-digital converter (89) receives the analog output signal from the metering device (85) and converts the signal into a digital output signal. A microprocessor 93 receives the digital output signal, which is representative of the magnitude of the electrical property (eg, voltage, resistance, conductivity, etc.) and analyzes it to determine the presence of an attack. If the microprocessor (93) detects the presence of an attack, then the attack alarm (95) is activated. Alternatively, the microprocessor activates a transmitter (not shown) that sends a signal to a receiver at a remote location and the receiver (which may be a separate device or an attack alarm component) activates an attack alarm. The attack alarm (ie half indicator) then signals a caregiver or wearer of the absorbent article to the presence of an attack. As discussed above, the signal may be auditory, visual and / or tactile, among others. The analog to digital converter 89 is a conventional device for converting analog signals into digital signal that can be read by a microprocessor. The analog to digital converter (89) of the present embodiment may be a separate device or may be a component of the microprocessor (93). For illustrative purposes, the electrical property will hereinafter be referred to as resistance although, as noted above, it may be any of several suitable properties.

In one embodiment, the analog output signal from the metering device 85 is converted to a digital output signal and sent to the microprocessor 93 as illustrated in Figure 7 and explained above. While this and other illustrated embodiments described herein use a completely digital approach, it is understood that other examples may also use part or all of an analog approach, as would be generally understood by those skilled in the art. Referring to Figure 12, microprocessor 93 in instruction 200 collects and stores the resistance (R1) (or other electrical property) value of the digital output signal. In instruction 202 the microprocessor 93 compares the measured resistance value (R1) (broadly, the magnitude indicator value) to a borderline magnitude value (MTV) to determine whether the measured resistance is an indication of the presence of a attack (largely a first test).

If the comparison is not indicative of the presence of an attack (ie, the measured resistance value (R1) is less than the limit magnitude value), then the microprocessor (93) is instructed to repeat the above steps and continue collecting, storing and comparing subsequent resistance values until their comparison to the borderline magnitude value is indicative of the presence of an attack (ie, the measured resistance value (Rl) is greater than or equal to the borderline magnitude value, MTV) . If the comparison is indicative of the presence of an attack, then the microprocessor (93) activates the attack alarm in instruction (210). Alternatively, the microprocessor activates a transmitter (not shown) that sends a signal to a receiver at a remote location and the receiver activates the attack alarm as discussed above.

Typically, the value of borderline magnitude will correspond to the resistance of the chemosistor in the presence of the target VOC. As discussed above, a chemosistor will have varying degrees of sensitivity to different VOCs depending on the polymeric material used in the chemosistor and the VOC to be detected. Thus, borderline magnitude will vary depending on both the chemoresistor used and the VOC to be detected. The boundary magnitude values for different combinations of chemosistor and VOC may be determined experimentally, for example by determining the resistance of the chemosistor in the presence of the VOC to be detected (for example, using methods such as those described in the examples herein).

For example, a borderline magnitude value can be determined by determining the basic resistance level for a chemosistor in the absence of any VOC and the resistance level of the chemosistor in the presence of a target VOC. The borderline magnitude value for that particular combination of chemosistor / VOC can then be set at any resistance level between these two values. The particular choice of boundary magnitude values will vary depending on the desired sensitivity of the chemoresistor. Typically, a higher boundary magnitude value is chosen if it is desired to avoid false positive determinations of the presence of an attack and a boundary magnitude value is chosen if greater sensitivity of the chemoresistor is desired. In a non-limiting example, if the basic resistance of a chemosistor is measured at 10 kiloohms and the resistance of the same chemosistor is 3 Megaohms in the presence of a target VOC, then the threshold magnitude value of 1 Mega ohm may be suitable for that one. particular chemosistor / VOC combination to substantially avoid false positive readings.

In one embodiment of the present disclosure, a percent difference test is conducted on the resistance measured for the chemosistor 72 to determine the presence (or absence) of an attack on the absorbent article as the absorbent article is used by the user. In this embodiment, a proportional difference (e.g., a percentage difference) in the measured electrical property of the chemosistor over time is determined and this proportional difference is compared to a different boundary value to determine if an attack is present on the pants. Figure 8 schematically illustrates microprocessor (93) instructions for determining the percent difference in chemosistor resistance (72) and comparing the percent difference to a boundary difference value for determining the presence of an attack. In instruction 100, microprocessor 93 collects and stores in its memory a first resistance value R1 from the digital output signal. The microprocessor (93) then delays sampling for a period of time in instruction (102) before collecting and storing a second resistance value (R2) in instruction (104). The delay may be programmed or may be a function of the A / D converter (89) and / or microprocessor (93) sampling rate.

With the first and second stored resistance values (R1, R2), in instruction (106) the microprocessor (93) subtracts the first value (R1) from the second value (R2) and divides the difference result by the first value (R1). and multiply the resulting quotient by 100%. The resulting value is stored as a difference value (DIV) indicator in instruction (108).

In instruction 110, the resulting difference indicator value (DIV) is then compared to a boundary difference value (DTV) to determine if an attack is present. For example, if the difference indicator value (DIV) is greater than that of the borderline difference value (DTV), then this is indicative of the presence of an attack. As an example, the boundary difference (DTV) value may be a value between 10% and 20% (indicating a 10% and 20% increase in resistance due to the sorption of the target VOC by the chemosistor) or, more particularly, the value. of borderline difference can be about 15%. If the comparison of the difference indicator value with the borderline difference value is indicative of the presence of an attack, then, if there are no other indicators, the microprocessor (93) activates the attack alarm (95) in instruction (112) to inform the caregiver and / or user of the presence of an attack. If, however, comparing the difference indicator value (DIV) with the borderline difference value (DTV) is not indicative of the presence of an attack, then, if there are no more indicators, the microprocessor (93) is instructed to repeat the above steps to determine new difference indicator values and compare them to the borderline difference value until an attack is indicated. The percent difference test is intended to be more accurate (ie detect better attacks and detect false positives less frequently) than the conventional border magnitude test since the percent difference test is independent of the magnitude of the chemoresistor resistance before absorption. or adsorption of a VOC. The percent difference test focuses on the amount of resistance change and allows for more accurate detection of multiple gaps.

In another example of the difference mode, the instructions for microprocessor 93 may involve determining the percentage difference between previous successive resistance values compared to a current value, for example, the difference between a third resistance value (R3) and a second resistance value (R2) and the third value (R3) and a first resistance value (R1) Figure 9 schematically illustrates the microprocessor instructions for this mode. In instruction 116, microprocessor 93 collects and stores in its memory a first resistance value R1 from the digital output signal for a first time. The microprocessor then delays for a period of time in instruction (118) before collecting and storing a second resistance value (R2) in instruction (120). In instruction (122) the microprocessor (93) delays and then collects and stores a third resistance value (R3) in instruction (124). With the stored values, the microprocessor 93 subtracts the second value (R2) from the third value (R3) and divides the resulting difference by the second value (R2) in instruction (126) to obtain a percentage difference. The percent difference is stored as a first difference indicator value (DIV 1) in instruction (128) and compared to the boundary difference value (DTV) in instruction (130) to determine if the comparison is indicative of the presence of an attack.

If the comparison of the first difference indicator value (DIV 1) is indicative of the presence of an attack, then the attack alarm (95) is triggered in instruction (132). If the comparison is not indicative of the presence of an attack then the microprocessor is instructed in (134) to calculate a second difference indicator value (DIV 2). by subtracting the first value (R1) from the third value (R3) and dividing the difference by the first value (R1). This second percentage difference (DIV 2) is stored as the second difference indicator value (DIV 2) in instruction (136). In instruction (138) the second difference indicator value (DIV 2) is then compared to the boundary difference value (DTV).

If the comparison of the second difference indicator value (DIV 2) with the boundary difference value (DTV) is indicative of the presence of an attack, then the attack alarm is triggered in instruction (132). If the comparison is not indicative of the presence of an attack, then the microprocessor is instructed to repeat the above steps to compare a new difference indicator value to the boundary difference value until an attack is indicated.

In the example above, if the first difference indicator value (DIV 1) or the second difference value (DIV 2) is above the boundary difference value (DTV), the microprocessor (93) triggers the attack alarm (95). It is also observed that only when the first indicator value and also the second indicator value are greater than the borderline value (ie both comparisons are indicative of the presence of an attack) would alarm (95) give the indication.

In another embodiment of the present disclosure a rate of change test is conducted for the measured electrical property of the circuit to determine the presence (or absence) of an attack. In this embodiment, a rate of change of electrical property measured over a period of time is determined, and this rate of change is compared to a boundary rate value to determine if an attack is present on the absorbent article.

In an example of this embodiment, the output signal from the metering device is converted to a digital output signal (via analog-digital converter 89, for example) and is received by microprocessor 93 as explained above and shown in Figure 7. Figure 10 schematically illustrates an example of microprocessor instructions (93) for determining the rate of change, for example, in the chemoresistor resistance (72) and comparing the rate of change to a boundary rate value for determining the presence of an attack. In instruction 142, the microprocessor 93 collects and stores in its memory a first resistance value R1 from the digital output signal in a first time. The microprocessor (93) then delays for a period of time in instruction (144) before collecting and storing a second resistance value (R2) in instruction (146). As explained above, the delay is determined by the sampling period of the A / D converter (89) and / or programmable by the instructions in the microprocessor (93).

With the first and second values (R1, R2) stored, the microprocessor (93) subtracts the first value from the second value and divides the resulting difference by the sampling period in instruction (148). The resulting value is stored as a rate indicator value (RIV) in instruction (150). In instruction 152, the microprocessor 93 compares the rate indicator value (RIV) with a boundary rate value (RTV) to determine if an attack is present. For example, if the rate indicator value (RIV) is greater than that of the border rate value (RTV), then this is indicative of the presence of an attack. If comparing the rate indicator value with the borderline rate value is indicative of the presence of an attack, then, if there is no other indicator, the microprocessor (93) triggers the attack alarm (95) to inform the caregiver and / or user for the presence of an attack on the instruction (154). If, however, comparing the value indicates <3oF rate with the boundary rate value is not clear of the presence of an attack, then if there are no other indicators, microprocessor 93 is instructed to repeat the above steps to determine new rate indicator values and compare them to the borderline rate value until an attack is indicated.

A suitable boundary rate value for a particular chemosistor / VOC combination may vary depending on the desired sensitivity of the chemosistor. For example, a boundary rate value for a chemosistor / VOC combination can be determined by measuring the chemosistor resistance level in the absence of any VOC (R1), exposing the chemosistor to the target VOC, and measuring the level of peak resistance of the chemosistor in the presence of the target VOC (R2). The R1 value can then be subtracted from the R2 value and the resulting difference divided by the time it took for the chemosistor to reach its peak resistance level after exposure to the target VOC (alternatively, the change in resistance could be measured by a predetermined amount. (for example, the change in resistance over 3 seconds could be used to calculate the rate of resistance change). This value (ohms / second) is a rate of resistance increase observed for the chemosistor in the presence of the target VOC. Any value below this observed rate of increase can be selected as the boundary rate value. Typically, a higher boundary magnitude value is chosen if it is desired to avoid false positive determinations of the presence of an attack and a boundary magnitude value is chosen if greater sensitivity of the chemoresistor is desired. In a non-limiting example, if the observed resistance increase rate for a particular chemosistor / VOC combination is 100 kiloohms / second, the boundary rate value will be some value below the observed increase rate, such as 80 kiloohms / second.

As with the percent difference test discussed above, the rate of change test is intended to be more accurate (ie detect better attacks and detect false positives less frequently) than the conventional borderline magnitude test since the rate of change test. It is independent of the magnitude of chemoresistor resistance prior to absorption or adsorption of a VOC and focuses on how rapidly the property changes.

As illustrated in Figure 11, in another example of the rate of change mode, instructions for the microprocessor may involve determining the rate of change between previous successive values compared to a current value (for example, the rate of change between a third value and a second value, and a third value, and a first value). This example is substantially similar to the instructions given in Figure 9 regarding the percentage difference mode, except that the first rate indicator value (RIV 1) between the third value (R3) and the second value (R2) is determined in instruction ( 160) and compared the boundary rate value (RTV) in instruction (162) and the second rate indicator value (RIV 2) between the third value (R3) and the first value (R1) is determined in instruction (164) and compared to the borderline rate (RTV) value in instruction (166).

In another embodiment, both the percentage difference mode and the rate of change mode can be combined into a single mode, where the attack alarm (95) is triggered only if both the difference indicator (DIV) value comparison with the Borderline difference value (DTV) compared to rate indicator value (RIV) with borderline rate value (RTV) are indicative of the presence of an attack. Alternatively, the attack alarm may be activated if the comparison of the difference indicator value with the borderline difference value or the comparison of the rate indicator value with the borderline rate value is indicative of the presence of an attack.

An example of this embodiment (not shown) is a combination of the examples of Figures 8 and 10 (using R2-R1) or Figures 9 and 11 (using R3-R2 and R3-R1) where the analog output signal from the measuring device is converted to a digital output signal and the microprocessor is instructed to compute both the rate indicator values and the difference indicator values and to compare both values to their respective boundary values to determine the presence of an attack using the digital output signal.

As previously discussed, certain polymeric materials are sensitive to water vapor, in addition to certain VOCs. Consequently, water vapor from the user's perspiration or from the external environment may be sorbed by the polymeric material and affect the resistance of the chemosistor. Then, in one embodiment, this water vapor is taken into account by determining the resistance of the chemosistor in the presence of a basic water vapor level. For example, the chemoresistor resistance can be measured over a period of time and used to calculate an average resistance value. This average resistance value considers water vapor that may have been sorbed by the chemosistor in the absence of an attack.

This average can then be used, for example, as the RI value in the rate of change or percentage difference test.

As will be apparent to those skilled in the art, numerous variations of the tests described above, as well as other conventionally known tests, may be performed by the microprocessor to determine if an attack is present on the absorbent article. It is understood that the exemplary values and ranges provided for the above tests / checks, including the exemplary values provided for the borderline difference value (DTV), the borderline rate value (RTV), the borderline magnitude value (MTV) ) and the values and time periods actually employed in the disclosure may change, depending on variables such as characteristics of the chemosistor material and the VOC to be detected, the type of electrodes used, electrode location on the absorbent article, user preference and any other variables affecting the indicator values and time periods used in the various tests.

When the elements of this disclosure or the embodiments thereof are introduced, the articles "a", "the", and "said" are intended to mean that there are one or more of the elements. The terms "comprising", "including" and "possessing" are intended to be inclusive and mean that there may be additional elements other than those listed.

In view mentioned above, it will be apparent that the various objects of the disclosure are achieved and other advantageous results are achieved.

As various changes may be made to the above constructions, products and methods, without departing from the scope of the disclosure, it is intended that all subject matter contained in the above description and shown in the accompanying drawings should be construed as illustrative and not in a limiting sense. . EXAMPLES EXAMPLE 1 Several chemoresists comprising various types of polymeric material were tested to determine the ability of chemoresists to detect the presence of various VOCs commonly present in urine and faeces.

Chemoresistors comprising (1) polyvinylethylene acetate (PEVA), (2) poly-N-vinyl pyrrolidone (PNVP), (3) polyisobutylene (PIB), or (4) polyepichlorohydrin (PECH) as the polymeric material, and carbon as the electrically conductive material, were evaluated for their ability to detect the presence of eight different VOCs (listed in Table 1) and water vapor. the chemoresistors were located on a chip (i.e., an integrated circuit pack) and the chip comprising the four chemoresistors was obtained from Sandia National Laboratories (Albuquerque, NM).

25 microliters of each VOC were placed independently in separate 500 milliliter bottles and the bottles were sealed. The compounds were heated at about 37 ° C for about 20 minutes. The bottles were then allowed to return to room temperature.

The chemoresistors were connected to an ohmmeter using standard measuring conductors that followed a particular chemosistor on the ohmmeter chip and the ohmmeter was connected to a computer through a serial port to obtain data. The chip comprising all four chemoresistors was suspended by the conductors on the top ohmmeter of the first bottle comprising trimethylamine, and the bottle was sealed with paraffin and pressed film sealed around the contacts. The chemoresistors were kept in the first sealed bottle for about 2 to 3 minutes at room temperature, and real-time measurements of the resistance of the first chemosistor (ie, the conductor-connected chemosistor) were recorded by the computer. After exposure to trimethylamine, the chip comprising the chemoresists was removed from the bottle and trimethylamine was allowed to desorb from the chemoresists for about 2 to 3 minutes. The chip comprising the chemoresistors was then suspended by the ohmmeter contacts from the top of the bottle comprising triethylamine and the bottle was sealed as described above. The chemoresistors were kept in the sealed bottle for about 2 to 3 minutes at room temperature, and real-time measurements of the resistance of the first chemosistor were recorded by the computer. After exposure to trimethylamine, the chip comprising the chemoresists was removed from the bottle and trimethylamine was allowed to desorb from the chemoresists for about 2 to 3 minutes. This process was repeated for each additional compound, each time recording the resistance measurements of the first chemosistor, until the chemosistors were exposed to each compound listed in Table 1. The whole process was then repeated three more times, and for each time resistance measurements were made for a different chemosistor.

Results are illustrated in Figures 14 to 17, which show the change in resistance when chemoresists comprising PEVA (Figure 14), PVNP (Figure 15), PIB (Figure 16) or PECH (Figure 17) were exposed to each compound. In general, the higher the resistance value, the more sensitive the chemosistor was to the presence of VOC. The drops in resistance between the times the chemoresistors were exposed to one of the VOCs, seen in Figures 14 through 17, are representative of the time period in which the VOCs were allowed to desorb from the chemistors. As can be seen from these results, the PEVA and PIB chemoresistors were especially sensitive to limonene and benzaldehyde, the PECH chemoresistors were especially sensitive to benzaldehyde and the PNVP chemoresistors were sensitive to several compounds, including trimethylamine, benzaldehyde, ammonia, mercaptoethanol and water vapor.

Claims (22)

An absorbent article comprising: a chemosistor arranged across a pair of spaced electrodes, the chemosistor comprising a plurality of electrically conductive particles and a polymeric material; a microprocessor capable of detecting a change in an electrical property of the chemoresistor; and a means for signaling the presence of a change in the electrical property of the chemosistor within the absorbent article; where the resistance of the chemosistor is capable of changing when the chemosistor is exposed to an analyte selected from the group consisting of water vapor, a volatile organic compound present in an attack, and combinations thereof where the attack is selected from the group consisting of urine, menstrual fluid, feces, blood and combinations thereof; and characterized in that the polymeric material is selected from the group consisting of polypichlorohydrin, poly (N-vinylpyrrolidone), polyisobutylene and polyethylene vinyl acetate (PEVA), and combinations thereof. Absorbent article according to Claim 1, characterized in that it also comprises a housing unit, wherein the housing unit comprises the microprocessor and the means for signaling the presence of a change in the chemoresistor electrical resistance within the article. Absorbent. Absorbent article according to Claim 1, characterized in that the means for signaling the presence of a change in the electrical property of the chemosistor within the absorbent article generates a signal selected from the group consisting of an auditory signal. , a tactile signal, a visual signal and combinations thereof. Absorbent article according to claim 1, characterized in that the volatile organic compound is selected from the group consisting of ammonium hydroxide, short chain C1 -C2 acids, C8 -C10 aldehydes of medium length, ketones, cresol, dimethyl disulfide, trimethylamine, limonene, acetic acid, methyl benzoate, benzamide, benzaldehyde, triethylamine, eschatol, mercaptans, hydrogensulfide, short chain fatty acids, methanethiol, dimethyl sulfide and combinations thereof. Absorbent article according to claim 1, characterized in that the chemosistor comprises 20% by weight to 60% by weight of the electrically conductive particles. Absorbent article according to claim 1, characterized in that it also comprises: a liner having a body facing surface oriented towards a user when the absorbent article is used and an opposite absorber facing surface the body-facing surface; an outer cover having an absorbent facing surface and an outer surface; and an absorbent structure positioned between the liner and the outer cover to absorb tangible exudates that penetrate the liner; where the chemosistor is on the outer surface of the outer casing. Absorbent article according to claim 6, characterized in that the chemosistor is covered with a coating. Absorbent article according to Claim 1, characterized in that it also comprises: a liner having a body facing surface oriented towards a user when the absorbent article is used and an opposite absorber facing surface the body-facing surface; an outer cover having an absorbent facing surface and an outer surface; and an absorbent structure positioned between the liner and the outer cover to absorb tangible exudates that penetrate the liner; where the chemosistor is on the absorber facing surface of the outer casing. Absorbent article according to claim 1, characterized in that the absorbent article comprises a first chemosistor and at least one additional chemosistor, wherein the resistance of the first chemosistor is capable of changing when the first chemosistor is exposed to a compound. volatile organic compound present in a first attack and the resistance of at least one additional chemosistor is able to change when the at least one additional chemosistor is exposed to a volatile organic compound present in at least one further attack, where the first attack is at least An additional attack are different attacks. Absorbent article according to claim 1, characterized in that the means for signaling the presence of a change in the electrical property of the chemosistor within the absorbent article comprises a transmitter capable of sending a signal to a receiver at a remote location. of the absorbent article, the receiver comprising an attack alarm capable of signaling the presence of a change in the electrical property of the chemosistor within the absorbent article. An absorbent article according to claim 10, further comprising a housing unit, wherein the housing unit comprises the microprocessor and the transmitter. Absorbent article according to claim 10, characterized in that the attack alarm generates a signal selected from the group consisting of an auditory signal, a tactile signal, a visual signal and combinations thereof. Absorbent article according to claim 10, characterized in that the volatile organic compound is selected from the group consisting of ammonium hydroxide, short chain C1-C2 acids, long Cs-C10 aldehydes. medium, ketones, cresol, dimethyl disulfide, trimethylamine, limonene, acetic acid, methyl benzoate, benzamide, benzaldehyde, triethylamine, eschatol, mercaptans, hydrogensulfide, short chain fatty acids, methanethiol, dimethyl sulfide and combinations thereof. Absorbent article according to claim 10, characterized in that the chemosistor comprises 20% by weight to 60% by weight of the electrically conductive particles. An absorbent article according to claim 10, further comprising: a liner having a body facing surface oriented towards a wearer when the absorbent article is used and an absorbent facing surface opposite to the surface. surface facing the body; an outer cover having an absorbent facing surface and an outer surface; and an absorbent structure positioned between the liner and the outer cover to absorb tangible exudates that penetrate the liner; where the chemosistor is on the outer surface of the outer casing. Absorbent article according to claim 15, characterized in that the chemosistor is a blanket with a coating. An absorbent article according to claim 10, further comprising: a liner having a body facing surface oriented towards a wearer when the absorbent article is used and an absorbent facing surface opposite to the wear surface. surface facing the body; an outer cover having an absorbent facing surface and an outer surface; and an absorbent structure positioned between the liner and the outer cover to absorb tangible exudates that penetrate the liner; where the chemosistor is on the absorber facing surface of the outer casing. Absorbent article according to claim 10, characterized in that the absorbent article comprises a first chemosistor and at least one additional chemosistor, wherein the resistance of the first chemosistor is capable of changing when the first chemosistor is exposed to a volatile organic compound present in a first attack and the resistance of at least one additional chemosistor is capable of changing when the at least one additional chemoresistor is exposed to a volatile organic compound present in at least one further attack, where the first attack is the At least one additional attack are different attacks. A method of detecting the presence of an attack within an absorbent article, the method comprising: providing a user with an absorbent article comprising a chemosistor arranged through a pair of spaced electrodes, the chemosistor comprising a plurality of electrically conductive particles. and a polymeric material; wherein the polymeric material is selected from the group consisting of polypichlorohydrin, poly (N-vinylpyrrolidone), polyisobutylene and polyethylene vinyl acetate (PEVA), and combinations thereof; monitor an electrical property of the chemosistor as the absorbent article is being used by the user, where the chemosistor resistance is able to change when the chemosistor is exposed to an analyte selected from the group consisting of water vapor, an organic compound. volatile present in an attack, and combinations thereof, where the attack is selected from the group consisting of urine, menstrual fluid, feces, blood and combinations thereof; and determining a proportional difference in electrical property over time and providing a difference indicator value corresponding to the determined proportional difference; and comparing the difference indicator value with a difference limit value to determine the presence of the attack, water vapor, or combinations thereof on the absorbent article. Method according to claim 19, characterized in that it also comprises communicating the presence of the attack, water vapor or combinations thereof to a caregiver and / or a user when the indicator value of difference compared to the value of The difference limit is indicative of the presence of the attack, water vapor or combinations thereof. The method of claim 19, wherein determining a proportional difference in electrical property over time comprises: determining a rate of change in electrical property over time and providing a rate indicator value corresponding to the determined rate of change; and comparing the rate indicator value with a rate limit value to determine the presence of the attack, water vapor, or combinations thereof on the absorbent article. Method according to claim 21, characterized in that it also comprises communicating the presence of the attack, water vapor or combinations thereof to a caregiver and / or a user when the rate indicator value compared to the The rate limit is indicative of the presence of the attack, water vapor or combinations thereof.